Regulation of dynamo-electric machines.



G.E.BARRY.

REGULATION OF DYNAMO ELECTRIC I9IIA()HI1I13S.-

1 nrmouxon rmm 81:21.20. 1905.

W by 1m w nessesz. Inventor:

Chafles E.Barr

PATENTED APR. 14, 1908.

UNITED STATES PATENT OFFICE.

CHARLES E. BARRY, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

REGULATION OF DYNAMO-ELECTRIC mcnnms.

To all whom it may concern:

Be it known that 1, CHARLES E. BARRY, a citizen of the United States,residing at Schenectady, county of Schenectady, State of New York, haveinvented certain new and useful Improvements in Re ulation ofDynamo-Electric Machines, of w 'ch the following is a specification.

My resent invention is a plicable more especia y to the regulation ofthose dynamo machines which are driven at speeds which may widely vary,as for example, the generators driven from the car' axles of railwaytrains.

In carrying my invention into ractice I provide means'for automaticallyecreasi the excitation of the generator as its speii d increases. Ilimit the maximum voltage of the machine, no matter What its speed, andirrespective of the amount of current flowing to the load circuit.

The features of novelty which characterize my invention are pointed outwith particularity in the appended claims.

' The invention itself will be better understood by reference to thefollowing description taken in connection with the accom panyindrawings, which represent diagrammatica y one embodiment of myinvention.

Inasmuch as my invention provides means for limiting the maximum voltageof the generator irrespective of its s eed and load, I find itparticularly applicab e to systems such as that shown in the patent toButtner, No. 734,298, July 21, 1903, in which the voltage of thegenerator is allowed to vary while the voltage at the translatingdevices is maintained practically constant by the interposition ofdevices which consume the surplus voltage. The devices employed byButtner, consist of iron wire resistances which, upon any tendency toincrease of current, increase in resistance and thereby maintain aproximately constant voltage at the trans ating devices." According to myinvention, I limit the voltage of the generator so that no matter howfast the generator may be driven the excess voltage to be consumed inthe iron wire resistance of the load never exceeds a moderate amount.

In the drawi s, the armature of the enerator to be regu ated isindicated at 1. he

main field winding isindicated conventionall at 2. An auxiliary buckingor diflerentia winding is shown at This is Specification 01 LettersPatent. Application filed September 20, 1905. was... 279,271

stancy of voltage at the oad.

Patented April 14, 1908.

arranged to be supplied with a voltage which varies at a greater ratethan the variation in speed of driving. To this end, it is connectedacross a resistance such as 4 having a high positive temperatureresistance coefiicient.

his resistance may consist of ironwire. In connectingiup the resistance4, it may if desired be connected directly across the armature 1, thoughI find it convenient to connect it, as shown in series with the winding2. In case it is connected across the armature 1, it is, of courseevident that a resistance of con stant value must be connected in serieswith it. B connecting the resistance 4 in series with t e winding 2,however, this extra re sistance becomes unnecessary.

The load for the generator may, of course, be of any desired characterbut it is indicated here as consisting of a number of lamps, 5, 6, 7 and8, having in series therewith iron Wire resistances, 9, 10, 11 and 12,res ectively,the purposes of which have alrea y been indicated. Ifdesired, a storage battery as 13 may be connected across the eneratormains to supply current to the loa when the voltage of the generatorbecomes too low and to receive current from the enerator at other times.An electrolytic ce 14 consisting, for example, of aluminium platesin asuitable solution may be placed 1n series with a circuit between theenerator and the storage battery 13, which a uminium cell permits assageof current from the generator to the oad but prevents the storagebattery from dlscharging' backward through the generator at times whenthe voltage of the generator is below normal.

With the use of an ordinary generator in a system such as described 1nthe Buttner patent, the voltage may in some cases rlse excessively abovenormal and thereby become so great that the iron wire resistances areincapable of preservin the desiredconv In accord ance with my invention,however, any excessive speed of the generator which tends to increasethe voltage is met in the first place by an increase in the resistanceof the iron wire resistance 4. This tends to keep down the current'inthe winding2. Moreover, as the resistance 4 increases in value much morethan the resistance of the winding 3, the division of current betweenthe resistances 4 and winding 3 is altered so that the winding carriesan increased proportion 4 small change of voltage of the generator 1smet by a multiplied demagnetizmg effect on the enerator field by reasonof the presence of t e iron resistance 4. The maximum variationofvoltage is hus rendered small.

It is obvious that numerous changes may be made in the embodiment of myinvention without departi from the spirit thereof, for which reason donotwish to be limited to the exact details shown and described. Thus, byway of example, I have mentioned the use of an iron wire resistance butit is obvious that resistances of any other suitable material having thesame effect may be substituted.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is,

1. In a self exciting dynamo electric machine, a main field winding, anopposing field winding, and means responsive to increase in voltage ofsaid machine for causing a more than proportional increase in current insaid opposing winding.

ing supplied with current from said arma ture, a resistance in seriestherewith having a high positive temperature-resistance coeflicient, andan opposing winding in shunt to said resistance.

3. The combination of a dynamo electric machine, a main field winding aniron resistance in series therewith, and an opposing field winding inshunt to said resistance.

4. In a dynamo-electric machine, the combination of an armature, twofield windin therefor, and means for causing. current in one wmdingtovary in a proportion greater and in the other winding ina proportionless than the variation of voltage of the generator.

In witness whereof I have hereunto set my hand this ISth'dag ofSeptember, 1905.

\ HARLES E. BARRY.

Witnesses:

HELEN Oaronn,

G. C. HOLLISTER.

